Brush contacts and holder assembly



April 20, 1965 e. M. FARRELL v BRUSH CONTACTS AND HOLDER ASSEMBLY Filed Dec. 17, 1962 INVENTOR 60) M FARRELL United States Patent 3,179,830 BRUSH CGNTACTS AND HQLDER ASSEMBLY Guy M. Farrell, Ehnhurst, Iih, assiguor to F. & F. Enterprises, Inc, Chicago, Ill., a corporation of Illinois Filed Dec. 17, 1962, Ser. No. 245,264

9 Qiaims. (Cl. 319-247) This invention relates to a brush contact and holder assembly. In particular, the invention is directed to a unique structure embodying these elements whereby highly effective results are achieved when the structure is employed in combination with commutators, slip rings and the like.

In applications where brush contacts and holders are employed, it is important to provide for maintenance in the continuity of electrical contact. For this reason, many brush holders are designed whereby the brushes are urged in a consistent manner into engagement with commutators or slip rings so that there will be no breaks in the passage of current. Brush holders of this type have been particularly designed for use in automobiles and in many other applications where vibrations, jolts and the like would cause the'brushes to move out of contact with the moving current carrying surfaces.

Brush holders which are provided with resilient means connected to the brushes have heretofore presented certain diificulties. Thus, these holders are more complicated, and, therefore, manufacturing and replacement costs require substantial outlays. Furthermore, in many instances, thedesign of the holders is such that it is more practical to replace a whole unit rather than to replace worn brushes. This situation also increases the expense associated with the use of brush contacts and holders of the type referred to.

It is an object of this invention to provide an improved brush contact and holder assembly which achieves highly effective results when the assembly is employed in combination with commutators, slip rings and the like.

it is a more particular object of this invention to provide brush. contact and holder assemblies which include a novel method of resiliently mounting the brush contacts whereby continuity in the passage of current is achieved even when vibrations, jolts and similar conditions are experienced.

ltis an additional object of this invention to provide a brush contact and holder assembly which eliminates difficulties experienced with prior art constructions as a result of the complexity and expensive nature of prior art constructions.

It is an additional object of this invention to provide a brush contact and holder assembly which is characterized by a simple brush holder construction, which includes a unique manner of retaining the brushes whereby improved electrical contact can be accomplished and wherein the brushes are releasably held by the. brush holder whereby replacement of Worn brushes is greatly 1 facilitated; J H

These and other objects of this invention will appear hereinafter, and for purposes of illustration but not of limitation, specific embodiments of this invention are shown in the accompanying drawings in which:

FIGURE"1- is an elevational view of a motor con- 3,17%,839 Patented Apr. 20, 1955 struction illustrating the brush holder assembly of this invention;

FIGURE 2 is a plan view illustrating the brush holder assembly;

FIGURE 3 is a cross-sectional view taken about the line 33 of FIGURE 2; and

FIGURE 4 is a cross-sectional view taken about the line 44 of FIGURE 2.

The structure of this invention comprises a device which includes a body portion having openings extending therethrough which are adapted to receive brush contacts. The body portion also carries a bracket member which is removably held thereon. Resilient means, which are preferably copper wire springs, interconnect the bracket member and the brush contacts received in the body portion. The brush contacts extend to points disposed outwardly of the body portion whereby they can be held in contact with a rotating commutator, slip rings or the like.

in accordance with the preferred form of this invention, the bracket member is held in the body portion by means of the terminal end of an electrical conductor. This terminal end is adapted to be inserted into a bore defined by the body portion and into an opening defined in the bracket member when the bore and this opening are in registry. In accordance with this invention, removal of the terminal end releases the bracket member and the brush contacts, and, accordingly, the

brush contacts can be replaced by simply disconnecting this terminal end. As a further distinctive feature of this arrangement, a necked-down portion is provided in the terminal end. When the terminal end is in position within the bore and associated bracket opening, the necked-down portion of the terminal end is disposed adjacent the bracket opening, and, accordingly, the bracket is adapted to pivot about this terminal end..

The accompanying drawings provide a more specific illustration of the concepts of this invention. FIGURE 1 illustrates mounting members 12 which are adapted to be associated with a motor (not shown). A pair of brush contact and holder assemblies 14 are connected to these mounting members by means of the bolts 16. A commutator ring 18 is situated whereby the brush contacts will be engaged with the surface thereof during its rotation. a

The assemblies 14 comprise a mounting plate 2% which forms a mount for brush'holder body portion 22. body portion illustrated is formed in two sections which are held together and secured to the mounting plate by means of the screw 24. s

The holder body portion defines a pair of openings 26 dimensioned to receive brushes 28. A pair of springs 36 are connected at one end to bracket member 32 and the other end of each of these springs .is wrapped around stud portion 34 of the brush contacts. Similarly, the

springs 36 are wrapped around tab portions 36 of the bracket 32. V

A bore 38 is formed in thebody portion 22 and this bore is adapted to be placed in registry with opening 4d defined by the bracket member 32. When the brush contacts 28 are to be positioned within the brush holder, the opening in the bracket member 32 is placed in registry with the bore 38, and the terminal end 42 of the conductor- 54 is then placed in the bore of the body Ci) portion. It will be appreciated that the terminal end should have an outer diameter substantially equal to the diameter of the bore 3-8 so that a pressure fit of the terminal end can be achieved. It will also be noted that the diameter of the terminal end is smaller in the central area thereof to provide a necked-down portion. As illustrated in FIGURE 4, when the bracket member receives the terminal end 42, it is still capable of freely pivoting about this end. It can be noted here that the electrical circuit provided by the device of this invention passes through brushes 28, springs 39, bracket 32 and terminal end 4-2. The springs press the bracket against the terminal end to insure a constant current carrying path.

As shown in FIGURES 3 and 4, the brushes 28 extend a short distance into the openings 26 defined in the body portion. The springs 33 are wrapped around the stud portions 34 so that a gripping relationship is achieved. Furthermore, the sections of the brushes extending into these openings are held therein by the engagement of the springs 349 with shoulders 46 formed at the end of the openings. Thus, the springs 30 serve to restrict movement of the brushes completely out of the openings, and, therefore, a uniform length of the brushes is exposed.

The device of this invention can obviously be easily assembled by first connecting the bracket 32 to the springs 34) and then connecting the brushes 28 to these springs. The brushes are then passed through the top of the body portion into the openings 26 and out the end of the body portion until movement is restricted by the shoulders 45. A slot 43 is defined in the upper portion of the body portion 22, and this slot receives the central section of the bracket 32. Furthermore, this slot communicates with the bore 38 whereby the opening 40 in the bracket member can be brought into registry with the bore. Finger tip pressure on top of the bracket 32 will serve to maintain the desired registry while the terminal end 42 is inserted into position.

In the operation of the device, the brushes 28 will normally both be in contact with the surface of a commutator or the like. In this connection, it is preferred that the ends of the brushes be normally positioned at about the location of the line shown in FIGURE 4. When the brushes are pressed slightly inwardly in this manner, the springs 30 will tend to compensate for any vibrations encountered by the brushes.

If the device of this invention is subjected to jolts or vibrations, electrical contact will still be maintained since the tendency toward moving of one brush away from the current carrying surface will increase the tend ency for the other brush to press against this surface. This arises due to the free pivotal mounting achieved by the connection with the terminal end 42. Clearly, if one of the brushes is pressed into an opening 26, the opposite bracket arm must move downtoward the opposite brush, and, therefore, a greater pressure reaction will take place.

The device of this invention is also particularly valuable since there is no need to dismount the brush holder when it is desired to replace a brush. Similarly, the brush holder need not be removed from its mounting on the plate 20 since the brushes can be reached by simply pulling out terminal end 42 whereby the bracket 32 can be removed. Brushes 28 can be replaced without discarding any other structural element.

It will be understood that various modifications can be made in the above described brush contacts and holder which provide the characteristics of this invention without departing from the spirit and thereof particularly as defined in the following claims.

That which is claimed is:

1. A device of the type described comprising an insulated body portion, a pair of openings defined in said body portion and extending therethrough, a bracket member adapted to be movably held by said body portion, said bracket member having spring holding end portions, the respective end portions being positioned at one end of said openings with said spring means extending into said openings and connected at one end to said end portions, a .pair of brush contacts connected to the opposite ends of said spring means and extending within said openings to points disposed outwardly of said body portion, means pivotally connecting said bracket to said housing whereby said end portions can move vertically relative to said openings, and means for connecting said bracket in an electrical circuit which includes said springs and said brushes.

2. A device of the type described comprising a body portion, openings defined in said body portion and extending therethrough, a pivotal bracket member adapted to be removably held by said body portion, resilient members connected at one end to said bracket member, brush contacts connected to the opposite ends of said resilient members and extending within said openings to points disposed outwardly of said body portion, and wherein said bracket member is removably held on said body portion by means of the terminal end of an electrical conductor, and wherein said bracket member pivots about said terminal end.

3. A device in accordance with claim 2 wherein the current path is formed by said brush contacts, said resilient means, said bracket and then through said terminal end.

4. A device of the type described comprising an insulating body portion, a pair of openings defined in said body portion and extending therethrough, a pivotal bracket member adapted to be removably held by said body portion, spring means connected at one end to said bracket member, a pair of brush contacts connected to the opposite ends of said spring means and extending within said openings to points disposed outwardly of said body portion, and including a slot defined in said body portion on the side opposite the extending ends of said contacts, said slot communicating with said opening and being dimensioned to receive said bracket member, a bore passing through said body portion in communication with said slot and adapted to register with an opening in said bracket member when the bracket member is received in said slot, said bore and said last mentioned opening being dimensioned to receive the terminal end of an electrical conductor, said terminal end serving to removably hold said bracket member on said body portion.

5. A device in accordance with claim 4 wherein said terminal end is necked-down in the area which is received by the opening in said bracket member whereby the bracket member is free to pivot about said terminal end.

6. A device of the type described comprising an insulating body portion, a pair of openings defined in said body portion and extending therethrough, a pivotal bracket member adapted to be removably held by said body portion, a pair of spring means each connected at one end to said bracket member, a pair of brush contacts connected to the opposite ends of said spring means and extending within said openings to points disposed outwardly of said body portion, and means at one end of said openings for restricting movement of said brush contacts whereby a portion of each is retained within said openings.

7. A device in accordance with claim 6 wherein said restricting means comprise shoulders formed at said one end of said openings, and wherein said spring means are wrapped around the top ends of said contacts and engage said shoulders to thereby hold said contacts in position.

8. A device in accordance with claim 7 including a slot defined in said body portion on the side opposite the extending ends of said contacts, said slot communi- 5 eating with said opening and being dimensioned to receive said bracket member, a bore passing through said body portion in communication with said slot and adapted to register with an opening in said bracket member when the bracket member is received in said slot, said bore and said last mentioned opening being dimensioned to receive the terminal end of an electrical conductor, said terminal end serving to removably hold said bracket member on said body portion.

9. A device in accordance with claim 8 wherein said terminal end is necked-down in the area which is received by the opening in said bracket member whereby 6 the bracket member is free to pivot about said terminal end.

References Cited by the Examiner UNITED STATES PATENTS 1,761,066 6/30 Bindschedler et a1. 310-247 1,948,268 2/34 Kitto 310247 2,987,639 6/61 Bayless et a1 310-247 FOREIGN PATENTS 1,116,280 1/56 France.

MILTON O. HIRSHFIELD, Primary Examiner. 

2. A DEVICE OF THE TYPE DESCRIBED COMPRISING A BODY PORTION, OPENINGS DEFINED IN SAID BODY PORTION AND EXTENDING THERETHROUGH, A PIVOTAL BRACKET MEMBER ADAPTED TO BE REMOVABLY HELD BY SAID BODY PORTION, RESILIENT MEMBERS CONNECTED AT ONE END TO SAID BRACKET MEMBER, BRUSH CONTACTS CONNECTED TO THE OPPOSITE ENDS OF SAID RESILIENT MEMBERS AND EXTENDING WITHIN SAID OPENINGS TO POINTS DISPOSED OUTWARDLY OF SAID BODY PORTION, AND WHEREIN SAID BRACKET MEMBER IS REMOVABLY HELD ON SAID BODY PORTION BY MEANS OF THE TERMINAL END OF ELECTRICAL CONDUCTOR, AND WHEREIN SAID BRACKET MEMBER PIVOTS ABOUT SAID TERMINAL END. 